Musical instrument



Nov. 11, 1941. c. w. RUSSELL v 2,262,335

MUSICAL INSTRUMENT Filed July 21, 19 39 3 Sheets-Sheet 1 IIIIIIIIIIIII"""""'I ",II'I,

Invented 6'. W Ems-9e Z L A ttorneys Nov. 11, 1941. c. w. RUSSELL 2,262,335

MUSICAL INSTRUMENT Filed July 21, 1939 S Sheets-Sheet 2 rFh A ttorneys? Nov. 11, 1941. c. w. RUSSELL 2,252,335

MUSICAL INSTRUMENT Filed July 21. 1939 3 Sheets-Sheet 3 In venior v C. W Fuss-ell ,depression in the sounding board of Patented Nov. ll, 1941 UNITED STATES PATENT OFFICE I MUSICAL INSTRUMENT Clarence W. Russell, LongtomKans. Application July 21, 1939, Serial No. 285,173

' (Cl. s4 1.1'5)

'6 Claims.

My invention relates generally to stringed'mu sical instruments, and particularly to instruments of this type which involve an inductive electrical pick-up unit arranged to operate a re production device at a distance from the instrument, and an important object of my invention is to provide arrangements of this type whose operation is characterized by absence of tone dls-- tortion and by uniformity in tone volume, and wherein accurate reproduction of the music evolved by vibrating the different strings of the instrument in the course of .playing upon the same is assured.

Another important object of my invention is to provide arrangements of the character stated above wherein the pick-up unit associated with the strings of the instrument is devisedto enable the reproduction unit to reproduce equal volume regardless of the difference in diameter, vibration frequency, and amplitude of the string or strings, and regardless of the different planes in which the string or strings are vibrated.

Other important objects and advantages of my invention will be apparent from a reading of the following description taken in connection with the drawings wherein for purposes of illustration I have shown preferred embodiments of my invention.

In the drawings:

Figure 1 is a longitudinal sectional and side elevational view of a stringed musical instrument showing the incorporation therein of a pick-up and amplifying unit in accordance with the present invention.

Figure 2 is a top plan view of Figure 1. Figure 3 is an enlarged side elevational view of the pick-up unit removed from the instrument.

Figure 4 is a top plan view of Figure 3. Figure 5 is a right hand end elevational view of Figure 3.

Figure 6 is a transverse vertical sectional view taken through the pick-up unit alongside of one of the strings of the instrument and showingthe springs centered in the corresponding openings of the pole pieces.

Figure 7 is a side elevational view of an alternate form ,of pole piece.

Figure 8 is a left hand end elevational view of a pick-up unit showing the same mounted in a the instrument instead of flush therewith as in the em bc'diment illustrated in Figure l.

Figure 9 is aperspective viewof one of the pole pieces of the embodiment shown in Figures 3 to 6, inclusive.

" the bridge, the sounding board being devoid of the usual sound opening. Located inwardly of the .bridge I and in a position functionally related to that of the usual sound hole is the pick-up unit 5.

The pick-up unit 9 comprises a U-shaped permanent magnet l0 formed of flat rectangular cross section steel with the straight legs II and I2 thereof each formed with a pair of assembling bolt holes I3. 14 through which the assembling bolts I5, l6 pass. The respective assembling bolts pass also through respective pole plates IT, M which are thereby clamped directly against the inner surfaces of the respective magnet legs.

The pole plates l1, l8 each comprise, as shown in Figure 9, a generally rectangular magnetically permeable plate having its upper edge castellated by the presence of slots l9 defining individual pole-pieces 20 corresponding in number to the number of magnetically permeable steel strings 8 possessed by the instrument. Each pole-piece is formed with a circular opening 2l through which the corresponding string passes, each particular opening 2| beingpositionedsothat while the corresponding string passing therethrough is at rest the string will lie exactly in the axial center of the opening thereby providing for equalized magnetic cooperation between the steel stringand the pole-piece no matter in what direction orv plane the string may be vibrating, since in this arrangement the string cuts equally as many lines of force in any direction of vibration and while vibrating freely will approach the opposite sides of the opening at equally spaced distances therefrom. v

- The sizes of the openings 2| are not all the same, but these openings are gauged as to size or diameter so that their strings will not touch their sides when vibrated and so that the magnetic effect of each steel string on the corresponding pole-pieces of-the permanent magnet is the same regardless of the diameter of the strings and the amplitude and frequency of their vibration. In this way equalized volume reproduction is assured for the different strings by the reproduction device (hotshoWn') which the pick- I up unit .is to control through the medium of a suitable amplifying means such as that shown.

hinge connection 32 magneto! the pick-up connected to thesteel convenient opening in the'side wallet/the in;

described, said unitcomprising a U-shaped perstrument protected by a grommet 25. "The coils are connected as indicated at in series aiding relation producing in effect tric spacer u traversed by 29 may be used between thepole-plates-.-'

on the upper edges oi the legs of the magnet 20 at the opposite ends oi the coils 22,13" are non one coil having one end thereof grounded to the magnet A dielecthe wood screws 28,

by a suitable electrical conductor to the point 23. Although I have shown and described herein preferred embodiments of my invention, it is to be definitely understood that I do not desire to limit the application of the invention thereto, and any change or changes may be made in the materials, and in the structure and arrangement of the parts, within the spirit of the invention and the scope of the subjoined claims.

Having described the invention, what is claimed as new is:

electrical pick-up :'unit of, the character manent magnet having substantially straight legs, a pole piece secured to the inner side of andprojecting beyond one edge of each leg, a

magnetic bars 28, 21 each centrally traversed by the respective wood screws 28, 2! which anchor the pick-up unit operatively in place on the longitudinally wound coil on the projecting part .of eachr'pole piece, each projecting part comprising a magnetically permeable bar hinged at one end er the upper edge of the body of the projecting part, the lower-edge of said bar and the said upper edge being formed with comple- 'mentary semi-circular apertures, to define string sounding board '6, eitheronthe top, surface of the sounding board as shown in Figure 1 or in an accommodating depression SI formed in the top of the sounding board, the latter arrangement being called for in the case of an instrument Assembled as de-' having low-lying strings.

scribedthepaired castellations onthe opposed pole-pieces having their similarly sized openings accommodating openings while the bar is in closed position. '2. In a musical instrument having magnetizable vibratory strings arranged in side by side relation'g'anelectrical pick-up unit, said unit com- 2| axially aligned with'the corresponding strings 8. The bight of the permanent magnet is preferably placed adjacent thesm 'allor treble strings v of the instrument.

v A form of pole-plate Ila shown in Figure 7 of the'drawings permits installation and re-. moval of the pick-up unit on the instrumentv V. withoutv removing the strings thereof. This Pole-plate lla'hasa required member and sizes of semi-circular openings 2la to complement similar openings 2) formed in the upper edge of the plate. I A clamp-- ing screw 33 to be turned to lockthe. bar 3| in place, afterwthegstrings 8 have been'positioned in the openings. Thepoleplates Ila may be substituted for the i1 and I! where desired.

The coil of the pick-up unit 9, the steel strings the frame of the pick-up unit, and the chassis the amplifier, generally designated 35,-have a commonground. That-is to say, the shield 24 over the amplifier lead 24', and mechanically connected to the chassis of the amplifier 35, is electrically connected to the unit which is connected to. one end of .the'series: aidingcoils' and also carried bythe-bar u is arranged into the upper edge of the saidplate strings l-by connection f prising a permanent magnet characterized by pole-plates arranged across and longitudinally spaced along the strings, each pole-plates having thereon portions formed with string accommo" dating holes, the holes in the said portions being axially aligned and arranged v to receive the corresponding strings in concentrically spaced arrangement' while the strings are at rest, the said pole-plates inductive windings which is electrically individual polej pieces J the magnet and corresponding in number to the holes being circular and proportioned in diameter in'accordance with the size and amplitude of vibration of the individual strings. portion of its upper-edge cut 011 to provide the hinged bar 3| which hasthe: tonne endof the plate, and, the lower edge of this bar isformed with the 3. In a musical instrument having magnetiza- 'blewibratory' strings arranged in side by side re- 'lationfan-electrical pick-up unit, said unit comprising a permanent magnet characterized by pole-plates arranged across and longitudinally spaced along the strings; each pole-plates having thereon portions formed with string accommodating holes,'the holes in the said portions being 1 axially aligned and responding .string's arranged to receive the corin concentrically spaced arrangement while the strings are at rest, the said holes being circular and proportioned in diameter in accordance with the size and amplitude of vibration of the individual strings. and connected on said portions.

4. In a musical instrument, a plurality of magnetizable strings arranged in side by side spaced relation, an electrical pick-upunit comprising a horse-shoe permanent magnet having two substantially parallelly spaced legs, said legs being 1 substantially equally spaced from one side of said plurality of strings, said legs extending transversely with respect to the length of the strings, spaced along each leg of number of strings, said p0le -pieces projecting from the legs of the magnet in the direction of the strings and being aligned in pairs with respect to the individual strings, the pole-pieces of eachpairv being formed with string accommodating openings whereby each string passes v through the openings in two pole-pieces of opposite magnetic polarity.

5. In a musical instrument, a plurality of magnetizable strings arranged in side by side spaced relation ;an'electrical pick-up unit comprising a 2,2e2,sss

horse-shoe permanent magnet having two substantially parallelly spaced legs, said legs being substantially equally spaced from one side of said plurality of strings, said legs extending transversely with respect to the length of the strings, individual pole-pieces spaced along each leg of the magnet and corresponding in number to the number of strings, said pole-pieces projecting irom the legs of the magnet in the direction of the strings and being aligned in pairs with respect to the individual strings, the pole-pieces of each pair being formed with string accommodating openings whereby each string passes through the openings in two pole-pieces of opposite magnetic polarity, the openings in the paired pole-pieces being circular and concentric with respect to the string extending therethrough while the string is at rest, the diameters of the openings being proportioned to the diameter 01' the strings and the amplitude of their vibrations.

6. In a musical instrument a plurality of magnetizable strings arranged in side by side spaced relation, an electrical pick-up unit comprising a v horse-shoe permanent magnet having two substantially parallely spaced legs, said legs being substantially equally spaced from one side of said plurality of strings, said legs extending transversely with respect to the length 0! the strings, individual pole-pieces spaced along each leg of the magnet and corresponding in number to the number of strings, said pole-pieces projecting from the legs 01 the magnet in the direction of the strings and being aligned in pairs with respect to the individual strings, the pole-pieces of each pair being formed with string accommodating openings whereby each string passes through the openings in two pole-pieces of opposite magnetic polarity, a magnetizable pole-plate secured to each leg of the magnet and structurally and magnetically connecting the corresponding polepieces to the legs of the magnet, and a coil wound around each 01' said pole-plates between the related pole-pieces and the related magnet leg.

CLARENCE W. RUSSELL. 

